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Urinalysis: comparison between microscopic and flow cytometry analysis

INTRODUCTION: Urinalysis is a high demand procedure, with large amount of manual labor and poorly standardized. The purpose of this investigation was to analyze the performance of an automated system based on flow cytometry for routine urinalysis. MATERIAL AND METHODS: We analyzed 1,140 urine samples by light field microscopy and by flow cytometry (UF-100/SYSMEX). For the precision study of the UF-100, we calculated the within-run and between-run coefficients of variation using two different levels of commercial controls and four different urine samples. RESULTS: Erythrocytes and leukocytes counts by the two methods showed an agreement of 91% and 93%, respectively. Casts, epithelial cells and bacteria counts by the UF-100 showed a significant overlap when compared to microscopic analysis. Intra assay precision (within-run) ranged from 4% to 155% and interassay precision (between-run) varied from 3% to 25%, depending on the considered parameter. CONCLUSION: Flow cytometry is a precise and reproducible technique, with a strong correlation with the results obtained by microscopic analysis. Flow cytometry allows a better workflow and a new manner of reporting and interpreting routine urinalysis.

Urinalysis; Microscopic examination; Flow cytometry


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